Acremonium

Where It Is Found: Acremonium is naturally found in soils, decaying organic matter, and plant debris. It is also an agricultural contaminant. This genus can be parasitic or saprophytic to plants and other living fungi, and some species cause vascular wilts in trees.

Physical Characteristics: The growth rate of Acremonium colonies is moderately rapid. Colonies grow are compact and moist, becoming overgrown with loose, cottony hyphae which are white, gray or rose in color. The reverse side is either uncolored or pink to rose colored. Indoor growth requires extremely wet conditions, and does not grow very well at 37°C.

Potential Health Effects: Acremonium is a common type I & III allergen. Acremonium has been known to produce a toxin from the trichothecene group and may also give off an unpleasant odor due to the production of volatile organic compounds (VOCs). This fungus is associated with occupant complaints such as nausea, vomiting and diarrhea. Acremonium has been isolated from cases of mycetoma, onychomycosis, mycotic keratitis, infection of the cornea, and infections of artificial implants. The trichothecenes are potent inhibitors of DNA, RNA, and protein synthesis, and have been well studied in animal models. They are a known carcinogen.

Alternaria

Where It Is Found: Spores of the Alternaria species are dispersed by air currents and are usually a major component of outdoor air. Specimens of Alternaria are often found growing on carpets, textiles and horizontal surfaces such as window frames. It is commonly found in soil, seeds, and plants.

Physical Characteristics: Alternaria grows rapidly the colony surface is grayish white at the beginning which later darkens and becomes greenish black or olive brown with a light border. The reverse side is typically brown or black due to pigment production. Alternaria is a dry spore and is readily found in air samples as well as on tape lift samples.

Potential Health Effects: It is known to be a common allergen and is associated with hypersensitive pneumonia. Because of its small spore size, it is capable of being deposited in the nose, mouth, and upper respiratory system. Sores in the nose, injured skin, and nail infections are prime targets and are easily irritated by Alternaria. Acute symptoms include edema and bronchiospasms; chronic cases may develop pulmonary emphysema.

Mold Descriptions

Below is a list of some of the most commonly encountered mold types. Where they are typically found, their physical characteristics, and their potential health effects are listed below each type.

Acremonium

Alternaria

Arthrinium

Where It Is Found: Arthrinium is a widespread saprobe. Commonly found on dead plants, especially grasses and sedges, and often isolated from air near grassy places in the autumn.

Physical Characteristics: Arthrinium colonies grow rapidly and they usually occur in grape-like masses. The colonies appear woolly or cottony and white with brown spots on the surface. The reverse side of a colony is pale.

Potential Health Effects: Only one species of Arthrinium spp. is considered to be allergenic. There have been no reported cases of infections or toxin related diseases in humans or animals.

Ascospores

Where It Is Found: Ascospores grow well under a variety of conditions and many are known to be plant pathogens. Ascopspores can be found everywhere and commonly grow indoors on damp materials.

Physical Characteristics: The individual ascospores are extremely variable in size and shape. Ascospores do not have an attachment peg or scar, however some are distinguished as they are surrounded by a clear mucilanginous layer. Also, some ascospores have a germ slit or germ pore. Ascospores can be single-celled or multicelllular.

Potential Health Effects: Ascospores have not been extensively studied but it is considered to be an allergen. This group contains potential opportunistic pathogens, toxin producers, and allergens depending on the genus and species. Ascospores do present a human health risk but few have been reported to cause disease.

Aspergillus

Where It Is Found: Aspergillus is found on many different textiles and organic materials such as soil, plant debris, compost, stored grain, wood, paper, house dust, ventilation systems, and water-damaged building materials. Its moisture requirements vary widely with some preferring dryer conditions. It is often found in water-damaged carpet.

Physical Characteristics: The mold may be woolly or cottony in texture and shades of green, brown or black in color. The spores are similar to Penicillium spores and sometimes indistinguishable through non-viable analysis and, as such, are often classified as Penicillium/Aspergillus.

Potential Health Effects: Sixteen species of Aspergillus spp. have been documented as etiological agents of human disease but rarely occur in individuals with normally functioning immune systems. Aspergillosis is now the second most common fungal infection requiring hospitalization in the United States. Many Aspergillus species produce mycotoxins that may be associated with diseases in humans and other animals. Toxin production is dependent on the species or strain within the species and on the food source for the fungus. Some of these toxins are carcinogenic-including aflatoxins and ochratoxin. Aspergillus spp. is a common cause of extrinsic asthma with symptoms including edema and bronchiospasms, and chronic cases may develop pulmonary emphysema.

Aureobasidium

Where It Is Found: Aureobasidium is found on soils, forest soils, fresh water, aerial portions of plants, fruit, marine estuary sediments, and wood. It is a wet spore that is transferred by wind when dried out, or water droplets if wet. As a result, this mold is widespread where moisture accumulates indoors, especially in bathrooms and kitchens, on shower curtains, tile grout, window sills, textiles, and liquid waste materials.

Physical Characteristics: Aureobasidium grows moderately rapidly. This mold is yeast like, beginning cream to pink, and becoming dark brown and velvety with age. The reverse side is pale or black.

Potential Health Effects: Aureobasidium is a common allergen, causing Type I allergies and Type III hypersensitivity pneumonitis (Humidifier fever, Sauna taker’s lung.) There have been rare reports of isolates from skin lesions, keratitis, spleen abscess and blood isolate from immunocompromised individuals.

Basidiospores

Where It Is Found: Basidiospores are mainly found in gardens, forests, and woodlands. Spores disseminate during rain or in times of high humidity.

Physical Characteristics: Basidiospores are a general category of sexual spores that have been released from the basidium of a fungus. Basidiospores are an agent of dry wood rot, which may destroy the structure wood of buildings.

Potential Health Effects: Basidiospores are a ubiquitous type I & III allergen, saprobe and plant pathogen. Rarely opportunistic pathogens, Basidiospores may produce toxins, including amanitins, monomethyl-hydrazine, muscarine, ibotenic acid, and psilocybin.

Bipolaris

Where It Is Found: Bipolaris is a ubiquitous species that is a dry spore disseminated by the wind. It is often found on dead or dying plant debris, grasses, and in soil and is a plant pathogen of numerous plants, particularly tropical and subtropical plants. This fungus can grow in semi-dry environments.

Physical Characteristics: Bipolaris colonies grow rapidly. The texture of the colonies is velvety to woolly. The surface of the colonies is initially white to grayish brown and become olive green to black with a raised grayish periphery as they mature. The reverse sides are also darkly pigmented and olive to black in color.

Potential Health Effects: It has been reported to produce the mycotoxin sterigmatocystin, which has been shown to cause liver and kidney damage when ingested by laboratory animals. This fungus is associated with phaeohyphomycosis, a disease consisting of a group of mycotic infections including keratitis, sinusitis, and osteomyelitis. These infections most often occur in immune-compromised persons, although infections also occur in normal hosts. This fungus causes allergic fungal sinusitis, characterized by the presence of Bipolaris in the sinuses. In certain people with severe allergies, the large spores of this fungus can travel to the sinuses or upper respiratory tract, where they attach to the mucus and grow, producing an unrelenting allergic reaction that progressively and permanently damages the sinuses.

Cercospora

Where It Is Found: Cercospora is a dry spore that is usually disseminated via wind. It is common outdoors in agricultural areas, especially during harvest. It seldom grows indoors.

Physical Characteristics: Cercospora is a plant parasite mostly on higher plants, causing leaf spot. This spore is distinctive and not easily confused with other spore types.

Potential Health Effects: This fungus produces no known potential toxins.

Chaetomium

Where It Is Found: Chaetomium is found on a variety of substrates containing cellulose including paper and plant compost. It can be readily found on the damp or water damaged paper in sheetrock. Several species have been reported to play a major role in decomposition of cellulose-made materials. The process is especially rapid under moist conditions.

Physical Characteristics: Chaetomium colonies are rapidly growing, cottony and white in color initially. Mature colonies become grey to olive in color. From the reverse side, the color is tan to red or brown to black.

Potential Health Effects: Chaetomium is reported to be allergenic, as it may cause hay
fever or asthma. Chaetomium are among the fungi causing infections wholly referred to as phaeohyphomycosis. Fatal deep mycoses due to Chaetomium atrobrunneum have been documented. Brain abscess, peritonitis, cutaneous lesions, and onychomycosis may also develop due to Chaetomium. Unlike most other mold pathogens, there is medical evidence to suggest that people who are exposed to Chaetomium may have permanent neurological damage of the myelin sheath. Therefore, a noticeably high incidence of autoimmune diseases has been linked to exposure of this mold such as Multiple Sclerosis, Lupus, etc. It has also been linked to certain forms of Cancer. As with other fungal exposure, it also causes permanent DNA damage. This has been documented in several cases being researched during studies. Chaetomium is the only mold that inhibits cell replication.

Cladosporium

Where It Is Found: Cladosporium spp. is the most frequently found species in outdoor air in temperate climates. It is also found on dead plants, woody plants, food, straw, soil, paint, and textiles. It is often found indoors, usually in lesser numbers than outdoors. The dry conidia become easily airborne and are transported over long distances. Indoors, this fungus is often encountered in dirty refrigerators, on moist window frames, interior paint, paper, and textiles stored under humid conditions, and on the surface of fiberglass duct liners in the interior of supply ducts.

Physical Characteristics: Cladosporium colonies are relatively slow growing and are powdery or velvety olive-green to olive-brown. Cladosporium grows well between 0° C and 35° C.

Potential Health Effects: It is a common cause of hay fever and asthma and is a known allergen. It may also cause corneal infections and mycetoma, characterized by localized infections that involve cutaneous and subcutaneous tissue, fascia, and bone consisting of abscesses, granulomata, and draining sinuses, usually in immunocompromised hosts.

Curvularia

Where It Is Found: Curvularia is found in plant debris, soil, stored grains, and is a plant pathogen of tropical and subtropical plants.

Physical Characteristics: Curvularia Produces rapidly growing, woolly colonies. From the front, the color of the colony is white to pinkish gray initially and turns to olive brown or black as the colony matures. From the reverse, it is dark brown to black.

Potential Health Effects: Curvularia is reported to be allergenic. It may cause corneal infections, mycetoma and infections in immune compromised hosts. This fugus is also reported as an ocassional cause of onychomycosis, ocular keratitis, sinusitis, mycetoma, pneumonia, endocarditis, cerebral abscess, and disseminated infection. Most cases are from immunocompromised patients.

Dictyosporium

Where It Is Found: It is found in terrestrial and freshwater habitats, and is a common saprobe of submerged lignocellulose substances.

Physical Characteristics: Dictyosporium colonies may appear dark brown, green-black, or black.

Potential Health Effects: There is no information available concerning Dictyosporium allergenicity or toxicity.

Drechslera

Where It Is Found: Drechslera is commonly found on plant debris, soil, and a variety of substances indoors in tropical to subtropical areas. The fungi will survive for several years in dead clippings or infected grass plants. It is an opportunistic pathogen to certain plant/ grass and animal species. The spores will then germinate in a film of moisture and infect the leaves, causing the spotting.

Physical Characteristics: Drechslera colonies grow rapidly. Both the surface and reverse of the is colony color is velvety or wooly and initially white becoming olive brown to black

Potential Health Effects: Drechslera is one of the most commonly found allergenic spores. It is known to cause allergenic symptoms such as hay fever and asthma. This fungus is also a potential toxin producer.

Epicoccum

Where It Is Found: Epicoccum is commonly found as a secondary invader in plants, soil, grains, textiles, and paper products where Cladosporium and Aureobasidium are present. Epicoccum is frequently isolated from air and occasionally occurs in house dust. Epicoccum is considered to be a dry weather spore and is very resistant to changes in water activity; the fungus has been known to resume growth after extended periods of drying.

Physical Characteristics: Epicoccum grows rapidly and produces woolly, cottony, or felty colonies. From the front, the colonies are yellow, orange, red or pink initially and become greenish brown to black through aging. From the reverse, the same color is observed but is usually more intense than in the front view. Black dots may be observed on the colony surface.

Potential Health Effects: Epicoccum is reported to be a type I allergen but not in a high frequency. Some allergenic symptoms are associated with the respiratory tract and include allergic rhinitis, asthma, and hypersensitivity pneumonitis. Due to the ability of this fungus to grow at 37°C, it can cause infection of skin in humans.

Eurotium

Where It Is Found: Eurotium species are the sexual states of Aspergillus species. Eurotium is likely to be present along with related Aspergilli if growth has been long term and the nutrients of the substrate are conducive for the conversion to sexual phase. It generally occurs on substrates low in moisture; very common in stored seeds, grows also on textiles, leather, and materials coated with resins and lacquers, such as furniture.

Physical Characteristics: Eurotium is characterized by whitish to bright yellow spherical fruiting bodies.

Potential Health Effects: Health effects, allergenicity, and toxicity of Eurotium are closely related to Aspergillus and, for the most part, have not been studied apart from that primary phase.

Fusarium

Where It Is Found: This mold is found in soil, plants, and grains. It requires very wet conditions to grow and is often found in humidifiers. It is a wet spore so it does not generally appear in air samples.

Physical Characteristics: Fusarium grows rapidly. From the front, the color of the colony may be white, tan, cream, salmon, cinnamon, yellow, red, violet, pink, or purple. From the reverse, it may be colorless, tan, red, dark purple, or brown.

Potential Health Effects: Fusarium is allergenic and is often associated with eye, skin and nail infections, and readily infects burn victims. It is known to produce trichothecene toxins, which effect the circulatory, alimentary, skin and nervous systems.

Myxomycetes

Where It Is Found: is commonly found in forested areas where bark, soil, dung, and leaf litter are present; however, it is occasionally found indoors. Aquatic Myxomycetes have been found in swamps and streams. Most Myxomycetes are widely distributed.

Physical Characteristics: Being on the border of the plant and animal kingdoms, Myxomycetes are not considered true fungi. Myxomycetes exhibit characteristics of protozoans and fungi. It is indistinguishable from Smuts under 600X microscopy.

Potential Health Effects: Myxomycetes produces no known potential toxins.

Non-Sporulating Fungi

Non-sporulating fungi refer to molds that fail to produce spores either because they have lost this ability, conditions were not suitable or requires very long periods to produce spores. Unless distinctive spore types are formed, identification may not be possible. Frequently non-sporulating colonies are produced by basidiomycetes (mushrooms) which usually do not produce fruiting structures on lab media. Fungi that are strictly non-sporulating are called mycelia sterilia (sterile mycelia).

Nigrospora

Where It Is Found: Nigrospora is ubiquitous and found in cosmopolitan areas. It is especially abundant in warm climates. It is found in decaying plant material and soil. It travels by an active discharge mechanism and does not require wind or rain. It is rarely found growing indoors. It occurs on parasites on living grasses but is also present on dead ones.

Physical Characteristics: Nigrospora often appears as white wooly colonies growing fairly rapidly. Color of the colony is white initially and then becomes gray with black areas and matures to black eventually on both front and reverse.

Potential Health Effects: Nigrospora is reported to be allergenic. There have been extremely rare cases of human infection caused by Nigrospora.

Odium

Where It Is Found: Odium is very common and is an obligate parasite on leaves, stems, flowers, and fruits of living higher plants. It grows well in environments with high humidity and moderate temperatures.

Physical Characteristics: Odium appears as white powdery spots.

Potential Health Effects: No information is available on Odium regarding health effects or toxicity. Allergenicity has not been studied.

Other Colorless

All non-distinctive unidentifiable colorless spores seen on spore trap samples are placed into this category. These are all the genera described by the sentence: Spores do not have distinctive morphology and would be categorized as “other colorless” on spore trap samples.

Other Brown

All non-distinctive unidentifiable brown spores seen on spore trap samples are placed into this category. These are all the genera described by the sentence: Spores do not have distinctive morphology and would be categorized as “other brown” on spore trap samples.

Penicillium

Where It Is Found: It is commonly found in soil, food, cellulose, paint, grains, and compost piles. It can be found in carpet, wallpaper, and in interior fiberglass duct insulation.

Physical Characteristics: Penicillium colonies are rapid growing. The colonies are initially white and become blue green, gray green, olive green, yellow, or pinkish in time and have a velvety, wooly, or cottony texture.

Potential Health Effects: is reported to be allergenic (skin) and it may cause
hypersensitivity pneumonitis and allergic alveolitis in susceptible individuals. It can cause other infections such as keratitis, penicilliosis, and otomycosis. Some species can produce carcinogens and mycotoxins that are known to damage internal organs.

Periconia

Where It Is Found: Periconia is a widespread outdoor fungus commonly found in soil, blackened and dead herbaceous stems and leaf spots, grasses, rushes, and sedges. It is almost always associated with other fungi. The Periconia species is rarely found growing indoors.

Physical Characteristics: Generally, it is difficult to distinguish Periconia spores from the Smuts, Myxomycetes, and other round, brown spore types.

Potential Health Effects: There are occasions where Periconia has been implicated in mycotic keratitis, but this is relatively rare.

Pestalotiopsis

Where It Is Found: Pestalotiopsis species are known as plant pathogens and is commonly found on leaves, stems, twigs, and barks. Some members of Pestalotiopsis are able to grow on polyurethane, which is a synthetic polymer found in many homes.

Physical Characteristics: Pestalotiopsis is observed on plants as a gray spot or lesion.

Potential Health Effects: No information is available on Odium regarding health effects or toxicity. Allergenicity has not been studied.

Pithomyces

Where It Is Found: Pithomyces is found mainly growing on decaying plants, grasses, and soils. It may grow on paper but is not prolific indoors.

Physical Characteristics: Pithomyces colonies are typically tan to brown.

Potential Health Effects: This fungus has demonstrated allergenic activity; it is also considered an etiologic agent in immunocompromised patients. It produces a mycotoxin called sporidesmin known to be pathogenic in animals, causing liver damage and facial eczema.

Polythrincium

Where It Is Found: Polythrincium’s natural habitat is on leaves. Also, spores may be seen in dust as part of the normal influx of outdoor microbial particles. It is not known to grow indoors.

Physical Characteristics: Not well known.

Potential Health Effects: No information is available regarding health effects, or toxicity. Allergenicity has not been studied.

Rusts

Where It Is Found: Rusts are found on grasses, flowers, trees, and other living plant materials. Rusts do not grow indoors unless their host plants are present.

Physical Characteristics: Rusts produce red or rusty to orange spores.

Potential Health Effects: Rusts are a Type I allergen.

Scopulariopsis

Where It Is Found: Scopulariopsis is commonly found in soil, decaying wood, and various other plant and animal products. In indoor environment Scopulariopsis is found on dry walls, cellulose board, wallpaper, wood, mattress dust, carpets, shoes and wood pulp. This fungus has a relatively high water activity.

Physical Characteristics: Scopulariopsis has a moderately rapid growth rate and colonies are velvety to powdery in texture. The colony color is white initially becoming light brown or tan as it matures. Some species may even form dark – colored colonies.

Potential Health Effects: Very little is known about the health effects of this fungus. Certain species may be involved in human onychomycoses or pulmonary mycoses.

Smuts

Where It Is Found: Smuts are parasitic plant pathogens which require a living host to complete their life cycle and are not usually found growing indoors. Smuts are most often found on corn, grass, weeds, flowering plants, and other fungi; they are usually disseminated by wind.

Physical Characteristics: They are called smuts because they form black powdery spore masses that resemble soot or smut. Smuts are indistinguishable from Myxomycetes and Periconia under 600x microscopy.

Potential Health Effects: Smuts are type I allergens.

Spegazzinia

Where It Is Found: Spegazzinia is most commonly found in warm-temperate to tropical areas in soil and on dead leaves, stems, trees, and other various kinds of plant debris.

Physical Characteristics: Spegazzinia colonies are considered relatively slow growing, and are brownish-black to black in color.

Potential Health Effects: No mycotoxin production or pathogenicity in humans is reported. Allergenicity effects have not been studied.

Sporothrix

Where It Is Found: The fungus occurs in soil, wet or damp wood, living or decomposing plants, and peat moss.

Physical Characteristics: Sporothix is a thermally dimorphic fungus and the colony morphology varies depending on the temperature of growth. At 25°C, colonies grow moderately rapidly. They are moist, leathery to velvety, and have a finely wrinkled surface. From the front and the reverse, the color is white initially and becomes cream to dark brown in time. At 37°C, colonies grow moderately rapidly. They are yeast-like and creamy. The color is cream to beige.

Potential Health Effects: Sporothrix can cause sporotrichosis, but usually only in individuals that are immune compromised. Sporotrichosis is a chronic fungal infection that results when the mold enters the body where the skin is damaged or via the lungs. If it reaches the bloodstream, it can affect many other parts of the body.

Stachybotrys

Where It Is Found: Stachybotrys thrives on water damaged cellulose rich materials such as sheet rock, paper, ceiling tiles, cellulose-containing insulation backing and wallpaper. It is not known to compete well with other molds, but, if there is a high level and constant availability to water for an extended period of time, it may become the dominant mold. It is not very common outdoors.

Physical Characteristics: Stachybotrys produces cottony, rapidly growing colonies. The colony is white initially and turns to dark green and black from aging. It is shiny when wet

Potential Health Effects: The presence of this fungus in buildings is significant because of the mold’s ability to produce mycotoxins, which are extremely toxic. Exposure to these toxins can occur through inhalation, ingestion or dermal exposure. Persons with chronic exposure to the toxin report dermatitis, cough, rhinitis, nose bleeds, a burning sensation in the mouth and nasal passage, cold and flu symptoms, headache, general malaise, and fever. The toxins may also suppress the immune system. Inhalation may also induce pathological changes. Stachybotrys in high doses or chronic low doses it can be lethal.

Stemphylium

Where It Is Found: Stemphylium is found in soil, wood, and decaying vegetation. Some species found on leaves and are plant pathogens. Although Stemphylium is rarely found growing indoors, it may be seen in dust as part of the normal influx of outdoor particles.

Physical Characteristics: Colonies of Stemphylium grow rapidly. They are velvety to cottony in texture and gray, brown, or brownish-black.

Potential Health Effects: Stemphylium is a known Type I allergen.

Tetraploa

Where It Is Found: Natural habitat includes leaf bases and stems just above the soil on many kinds of plants and trees.

Physical Characteristics: Tetraploa forms in colonies that are brownish in color.

Potential Health Effects: The only reported human infections are two cases of keratitis (1970, 1980) and one case of subcutaneous infection of the knee (1990). No information is available regarding other health effects or toxicity. Allergenicity has not been studied.

Torula

Where It Is Found: Torula is a saprophyte (weak parasite) in mild areas on soils, dead wood, leaves, food, hay, textiles, and in the air. This fungus can also be found indoors on cellulose-based materials.

Physical Characteristics: Torula is light grayish-brown and powdery.

Potential Health Effects: reported to be a Type I allergen and a possible cause of hay fever and asthma.

Ulocladium

Where It Is Found: Ulocladium is commonly found as a saprophyte on plant materials and soils. Indoors, it is found on drywall, tapestries, wood, and other organic material.

Physical Characteristics: Colonies are moderately fast growing, usually appearing olive-brown, rusty-brown, black, or grayish), with a texture that is granular to velvety.

Potential Health Effects: This mold is reported to be a major allergen, capable of causing hay fever and asthma. It is also known to rarely cause subcutaneous infections.

Yeast

Where It Is Found: Yeasts are found worldwide in a variety of natural habitats or organic substrates such as plant leaves, flowers, soil, and salt water. They can also be found on the skin surfaces and in the intestinal tracts of warm-blooded animals, where they might be considered parasites, but can live symbiotically.

Physical Characteristics: Yeast colonies grow rapidly and appear smooth & glabrous, or pasty, moist or dry, white to cream in color, but some maybe tan, pinkish or orange.

Potential Health Effects: Yeast infections are among the most common fungal infections in humans. Their form ranges from localized cutaneous or mucocutaneous lesions, to fungemia or disseminated systemic mycoses. Some yeasts are reported to be allergenic. They may cause problems if a person has had previous exposure and developed a hypersensitivity. Yeasts may be allergenic to susceptible individuals when present in sufficient concentrations.

Zygomycetes

Where It Is Found: Zygomycetes are mostly terrestrial in habitat, living in soil or on decaying plant or animal material

Physical Characteristics: Zygomycetes are common, fast growing, and often overgrow and/or inhibit other fungi nearby.

Potential Health Effects: Species of Zygomycetes are known allergens, produce toxins, and cause adverse health effects.

Mold Descriptions: Client